/* Generate transitive closure of a matrix,
   Copyright (C) 1984, 1989 Free Software Foundation, Inc.

This file is part of Bison, the GNU Compiler Compiler.

Bison is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

Bison is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Bison; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */




#include <stdio.h>
#include "system.h"
#include "machine.h"


/* given n by n matrix of bits R, modify its contents
   to be the transive closure of what was given.  */



void
TC(R, n)
unsigned *R;
int n;
{
    register int rowsize;
    register unsigned mask;
    register unsigned *rowj;
    register unsigned *rp;
    register unsigned *rend;
    register unsigned *ccol;

    unsigned *relend;
    unsigned *cword;
    unsigned *rowi;

    rowsize = WORDSIZE(n) * sizeof(unsigned);
    relend = (unsigned *) ((char *) R + (n * rowsize));

    cword = R;
    mask = 1;
    rowi = R;
    while (rowi < relend)
    {
        ccol = cword;
        rowj = R;

        while (rowj < relend)
        {
            if (*ccol & mask)
            {
                rp = rowi;
                rend = (unsigned *) ((char *) rowj + rowsize);

                while (rowj < rend)
                    *rowj++ |= *rp++;
            }
            else
            {
                rowj = (unsigned *) ((char *) rowj + rowsize);
            }

            ccol = (unsigned *) ((char *) ccol + rowsize);
        }

        mask <<= 1;
        if (mask == 0)
        {
            mask = 1;
            cword++;
        }

        rowi = (unsigned *) ((char *) rowi + rowsize);
    }
}


/* Reflexive Transitive Closure.  Same as TC
   and then set all the bits on the diagonal of R.  */



void
RTC(R, n)
unsigned *R;
int n;
{
    register int rowsize;
    register unsigned mask;
    register unsigned *rp;
    register unsigned *relend;

    TC(R, n);

    rowsize = WORDSIZE(n) * sizeof(unsigned);
    relend = (unsigned *) ((char *) R + n*rowsize);

    mask = 1;
    rp = R;
    while (rp < relend)
    {
        *rp |= mask;

        mask <<= 1;
        if (mask == 0)
        {
            mask = 1;
            rp++;
        }

        rp = (unsigned *) ((char *) rp + rowsize);
    }
}
